In the United States, approximately 400,000 people have end-stage renal disease requiring chronic hemodialysis. Permanent vascular access sites for performing hemodialysis may be formed by creating an arteriovenous (AV) anastomosis whereby a vein is attached to an artery to form a high-flow shunt or fistula. A vein may be directly attached to an artery, but it may take 6 to 8 weeks before the venous section of the fistula has sufficiently matured to provide adequate blood flow for use with hemodialysis. Moreover, a direct anastomosis may not be feasible in all patients due to anatomical considerations.
Other patients may require the use of artificial graft material to provide an access site between the arterial and venous vascular systems. Patency rates of grafts are still not satisfactory, as the overall graft failure rate remains high. Temporary catheter access is also an option. However, the use of temporary catheter access exposes the patient to an additional risk of bleeding and infection, as well as discomfort.
Vascular access systems are known in the art. For example, U.S. Pat. No. 6,102,884 to Squitieri, U.S. Pat. No. 7,762,977 to Porter, and U.S. Pat. No. 8,079,973 to Harrig et al. describe implantable blood conduit systems which include (i) an extravascular blood conduit that has a proximal end adapted to couple with a first vascular segment of a patient and a distal end adapted to be inserted into a second vascular segment of the patient; (ii) a catheter having a proximal portion and a distal portion that, when implanted, floats freely within the second vascular segment; and (iii) a connector for fluidly coupling the proximal end of the blood conduit with the catheter with the proximal portion. It would be desirable to provide improved and/or alternative conduits or catheters that eliminate or at least minimize kinking, compression, or other obstructions.